You can use your Optane memory with a caching solution under linux. As @miguelinux said, in your bios you can enable your Optane memory to work as a normal nvme disk, instead of a RAID unit under Intel’s RST. I have 32gb as well. You can use it as root, normally. You can use it as a swapfile on that nvme disk. Or you can use it as a caching solution with bcache.
I have a Samsung 970 nvme and use it as root. I’m using the Optane memory as a cache for my HDDs with bcache. Optane’s 3D Xpoint offers so-so transfer speed, but awesome random I/O, which is perfect for compilation of small files or compilation units. Whenever I’m compiling stuff in my HDDs, bcache is using the Optane memory. CL offers bcache in bundle:
sudo swupd bundle-add bcache-tools
Some guides on how to use bcache:
EDIT: I see you don’t want to mess with bcache and zfs… I’m using xfs. Maybe you can enable L2ARC caching in zfs and use memory and the optane drive with it?